<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox"  v-model ="allChecked"/>
    </label>
    <span> <span>已完成{{itemFinishNum}}</span> / 全部{{todoList.length}} </span>
    <button class="btn btn-danger" @click="deleteSomeItem">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "Footer",
  props: {
    // todoList: {
    //   type: Array,
    //   default: []
    // }
    todoList: Array,
    checkAll: {
      type: Function,
      required: true,
      default: () =>{}
    },
    deleteSomeItem: Function
  },
  computed: {
    // itemFinish() {
    //   return this.todoList.filter(item => item.done).length;
    // }
    itemFinishNum() {
      //reduce 返回是不是第一个参数的值，
      return this.todoList.reduce((num,cur) => {
        if(cur.done) num++;
        return num;
      }, 0)
    },
    allChecked: {
      get() {
        return this.itemFinishNum === this.todoList.length && this.todoList.length;
      },
      set(newVal,b,c) {
        // console.log(newVal,b, c,"--------++++");
        this.checkAll(newVal)
      }
    }
  }
};
</script>

<style>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>
